A wide variety of commercially produced doughs are sold on the market today. Most prepared doughs are either intended to be frozen until a consumer is ready to use them or prepared for refrigerated storage. Frozen doughs are packaged in an unleavened state and a consumer must thaw out the dough and permit it to "rise" before baking. This thawing and leavening can be time consuming.
Refrigerated doughs, on the other hand, are most commonly leavened during the manufacturing process. This permits consumers to simply open the package of dough and immediately bake the dough. The convenience of refrigerated doughs as compared to frozen doughs makes refrigerated doughs more appealing to many consumers.
Refrigerated doughs are normally sold in individual containers providing a quantity of a dough to bake a single loaf of bread, a single batch of biscuits, etc. These containers are most commonly substantially cylindrical in shape and are formed of a pair of ends, which may be formed of a metal, attached at opposite ends of a tubular sidewall, which is frequently formed of a metal, paper and plastic composite.
In making such dough products, the manufacturer commonly places a predetermined portion of a substantially unleavened dough in the package and then leavens, or "proofs", the dough within the package. This has been found to be easier than proofing a large batch of dough and trying to place the leavened dough in a package without damaging the dough.
Proofing is most advantageously carried out at elevated temperatures, e.g. on the order of about 95.degree. F. This promotes the reaction of the chemicals in the leavening agent to ensure that the dough is reproducibly leavened in a predetermined period of time. The individual packages of unleavened dough may be individually heated during the proofing stage and the proofed packages may be packed later into cases (most commonly cardboard boxes containing a predetermined number, e.g. 24, of dough packages) for shipping. This methods proves to be rather costly and inefficient, though. It has been found much more economical to pack the dough packages into the cases in which they are sold prior to proofing and then proof the dough within the case.
Although packing the dough products into cases prior to proofing is more economical than proofing the dough packages one at a time, it is not without its flaws. As noted above, cases generally contain a number of packages of dough and are formed of cardboard or the like. Some of the dough packages will be positioned adjacent an exterior wall of the case while other dough packages are toward the center of the case and are spaced away from the sidewall. During the proofing process, the cases of unleavened dough are generally held in a controlled temperature environment which supplies convective heat to the case. The packages closer to a sidewall of the case will therefore tend to heat up to the desired temperature more quickly than the containers in the middle of the case.
This means that the manufacturer must leave the case in the controlled temperature environment for a longer period of time in order to ensure that all of the dough reaches the necessary temperature and stays at that temperature for the appropriate length of time. For example, a case of dough may take from about 50 minutes to about two hours in a 95.degree. F. environment, depending on the particular dough product, before all of the dough is sufficiently proofed; the same dough can be proofed in about 30 minutes to about 50 minutes if the cans are proofed individually.
In order to cool cases of proofed dough, the cases of hot dough are commonly placed in a holding area maintained at a reduced temperature, e.g. 38.degree.-40.degree. F., to chill the dough and arrest the leavening process. The dough will commonly continue to rise until the temperature of the dough drops below about 45.degree. F. This permits the dough to leaven further when the dough is baked so the product will rise in the oven.
The containers adjacent the walls of a case will tend to cool more quickly than the containers in the interior of the case. Thus, a significantly longer period of time must be allowed to cool all of the dough to refrigeration temperatures for storage and shipping than would be necessary if each container were proofed and cooled individually.
This difference in the heat treatment of dough depending on its position in a case introduces some variability in the quality of the product. Even though all of the dough products in a case may include dough formed in the same batch and be packaged in an identical manner, the packages adjacent the walls of the case will be held at an elevated temperature for a longer period of time and will be heated and cooled more quickly than will the inner packages, resulting in uneven proofing conditions for different packages within a single case.
In present manufacturing techniques, cases filled with packaged dough products as described above are frequently arranged on pallets and these pallets are passed through a heated chamber to heat the dough. Although this further simplifies handling of the dough products, it also adds to the disparity in proofing conditions from one package of dough to the next.
As explained above, temperature differentials arise within a case between those packages closest to the exterior of the case and those more centrally positioned within the case. The same problem tends to arise when these cases are arranged on a pallet--those cases closer to the perimeter of the pallet will heat and cool more quickly than the cases toward the center of the pallet. Accordingly, heating dough products which are packed into cases introduces some variation in proofing conditions for dough products depending upon their position within the case and packing those cases on a pallet will add even greater variability to the proofing process from one dough product to the next. Since cases may be stacked atop one another on a pallet, this can further compound the problem in that some of the cases on a pallet will be entirely surrounded by other cases. Hence, the proofing conditions experienced by dough in a package adjacent a sidewall of a case positioned peripherally on a pallet will differ significantly from the conditions experienced by dough in a package toward the center of the centermost case on a pallet.
One other problem with the current mode of proofing dough products is that it takes much longer than comparable proofing of individual packages of dough. As explained above, the innermost dough packages will take longer to reach the target temperature and will take significantly longer to cool to refrigeration temperatures. This will obviously affect processing times of the dough, forcing a manufacturer to leave a pallet of dough products in the heating tunnel for a longer period of time, and to spend more time cooling the dough to arrest leavening, than would otherwise be necessary to proof or cool individual packages of dough.
As an example, proofing of a pallet containing cases of substantially unleavened dough products must generally be heated in a chamber maintained at about 95.degree. F. for at least about 50 minutes, and perhaps as long as about 2 hours; this time will depend on the product, the number of cases on the pallet (which may range from about 70 cases to over 400 cases, depending on the size of the case) and the degree of leavening desired. Cooling this same pallet by placing it in a cooled storage area maintained at about 38.degree.-40.degree. F. can take as long as a week, with leavening continuing until the temperature is low enough to arrest the process, which can be as long as 2 days. If the same dough packages were individually heated and cooled under the same conditions, proofing could be carried out in about 30 minutes and they would cool to refrigeration temperatures in about 2 hours.
Accordingly, it would be desirable to provide a system for proofing packaged dough products that allow packaged dough products to be uniformly proofed in cases without regard to the relative position of the package within a case or that case's position on a pallet. Furthermore, it would be advantageous to provide a means for rapidly heating the dough in such cases to the desired proofing temperature and rapidly cooling the dough to arrest leavening.